Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Neutrophils are a type of white blood cell that play a crucial role in the body's innate immune response by engulfing and destroying pathogens. They are the most abundant type of white blood cells and act as first responders to infection.
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Neutrophils are produced in the bone marrow and have a short lifespan, typically surviving only a few hours to a couple of days.
They use a process called phagocytosis to engulf and digest microorganisms and cellular debris.
Neutrophils release enzymes and antimicrobial proteins from their granules to kill pathogens.
They can form neutrophil extracellular traps (NETs) by expelling their DNA to trap and neutralize microbes.
High levels of neutrophils in the blood can indicate an ongoing infection or inflammation, while low levels may suggest an impaired immune system.
The process by which cells, like neutrophils, ingest or engulf other cells, particles, or pathogens.
Granulocytes: A category of white blood cells characterized by the presence of granules in their cytoplasm; includes neutrophils, eosinophils, and basophils.
Innate Immune Response: The non-specific first line of defense against pathogens involving physical barriers, immune cells like neutrophils, and various molecular mechanisms.